Saab maintenance #1 – Cooling system

There’re many things I like to blog about, but most of the time, I didn’t because I was simply lazy to post.


However, there’s one area of topics I like to blog moving forward, is a chronological recount of the car maintenance activities I have carried out on my Saab 93 Sports Sedan. I thought with the blog, I could build a knowledge base out of it, for future reference purposes, be it on my current or future ride.

And we shall start with what had happened over the weekend, as I was driving in a hot afternoon (my scangauge told me that the ambient temperature was somewhere between 36-37 °C)

A very familiar warning beep chimed off . The car SID (Saab Information Display) displayed a intimidating  “A/C off due to high engine temperature” message.  My instant reaction was to look at the water temperature gauge on the car’s electronic instrument cluster. The gauge needle was already at the 3/4 mark, close to the ‘Red’ danger mark. I glanced through my scangauge, the exact reading of the water temperature was 125°C, and then subsequently hovered between 126°C to 128°C.

My first thought was that the cooling fan must have given way, as I had experienced similar anomaly in my previous car. I thought I could at least keep the temperature down by cruising on the highway as the result of the onrushing air, which worked the previous incident. This time however, it didn’t work at all and I was starting to sweat over the thoughts of driving the car under this condition.

After some experimenting, the problem not only did not go away, and I got a new SID message “Hot engine. Make a safe stop. Run engine on idle“. If the previous warning message did not get into me, this one surely had. I had no choice but to call a tow truck, and had it towed to a SAAB workshop.

When we were at the workshop, the mechanics was able to quickly confirmed that the radiator fan at the driver side (i.e. right fan) had malfunctioned.  I was advised to have the fan relay replaced as well, so eventually we had both items (fan and relay) changed. It was a relatively quick job for the mechanics. And as I thought we had the problem fixed, I shortly found out it was not as I drove the car out for a spin. The water temperate escalated from 60°C to 120°C within minutes, and I had to drive the car back to the workshop again to have the problem reassessed.

The mechanics instantly determined that we should take alook at the coolant thermostat, just as they were giving me a heads up as I drove the car for a test drive. Sure enough, when they took out the thermostat, the solenoid was closed, which means that the coolant had never flow through the radiator system to cool the engine down. And this explains the reason for the escalating temperature, even with a functional radiator fan. You see, the coolant fluid is the one that actually conducts the heat away from the engine, so no prize for guessing what happen when the coolant fluid does not flow through the radiator system!

So a new thermostat was replaced, along with the radiator pressure cap, which got brittle by the extreme heat. To be doubly sure, the mechanics put the car on stress test by turning on the heater, and constantly depressed the accelerator pedal for 5 minutes to keep the engine running at 3000rpm. The temperature rose as expected, but stabilized at 85°C, so it was promising.  So it was a job finally well done, and the problem finally got resolved.

Finally, the damage for the parts

  1. Radiator Fan – $699
  2. Radiator Fan control/relay – $299
  3. Coolant Thermostat – $90
  4. Radiator Cap – $20

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